1. Field
The present invention relates to a drum type washing machine having the same. More particularly, the present invention relates to a cylindrical rotating tub body, which is formed by rolling a plate such that both ends of the plate are connected to each other, and a drum-type washing machine having the same.
2. Description of the Related Art
In general, a drum-type washing machine is a device that washes laundry loaded in a drum by moving the laundry upward and then dropping the laundry from the top to the bottom of the drum. As disclosed in Korean Patent Unexamined Publication No. 2006-107036, a drum-type laundry machine according to the related art includes a housing forming an external appearance of the washing machine, a water tub, which is installed in the housing to contain water therein, and a rotating tub, which is rotatably installed in the water tub and rotates by receiving the rotating force generated from a driving motor. Therefore, as the rotating tub rotates in the water tub, the laundry moves upward together with washing water along an inner peripheral surface of the rotating tub and then drops, so that the laundry is washed.
The rotating tub includes a cylindrical rotating tub body, which is open at a front surface and a rear surface thereof, a front cover, which covers a front surface of the rotating tub body and has an opening at a center portion thereof to allow the laundry to be introduced into the rotating tub body, and a rear cover, which covers a rear surface of the rotating tub body and receives power from the driving motor. The rotating tub is provided at an inner peripheral surface thereof with a plurality of lifters, which are spaced apart from each other in the circumferential direction to lift the laundry upward.
Recently, a drum-type washing machine capable of improving washing efficiency using a concave-convex structure has been suggested. According to the above drum-type washing machine, a plurality of concave-convex sections are provided at an inner surface of a rotating tube body such that the laundry can be washed by the friction with the inner peripheral surface of the rotating tub, and lifter installation sections are formed in the circumferential direction alternately with the concave-convex section, so that the washing performance is improved due to the concave-convex structure.
However, since the concave-convex sections and the lifter installation sections are alternately installed on the inner peripheral surface of the rotating tub body, a strength of the concave-convex sections is increased due to the irregular structure thereof, but a strength of the lifter installation section is decreased due to an installation hole to install the lifter.
Accordingly, if the rotating tub body is manufactured in a cylindrical shape by rolling a plate having a predetermined length and width after forming the concave and convex structure and the lifter installation section on the plate, the lifter installation section having a relative low strength is extremely deformed as compared with the concave-convex structure. As a result, although the rotating tub body must be uniformly deformed into the cylindrical structure through the rolling process, the rotating tub body may be irregularly deformed about the lifter installation section.